The invention relates generally to methods, semiconductor devices, and products useful in object detection and ultrasonic distance measurement applications.
Automated object detection and distance measurement is useful in a variety of applications. Distance can be measured using a number of different techniques including radar, sonar, optical reflection, and so on. In some environments there may be a number of different unrelated entities performing distance measurements using similar techniques. For example, vehicle manufacturers increasingly include obstacle detection and distance measurement systems in vehicles for applications such as collision avoidance and parking assistance. These systems use ultrasonic acoustic echo detection to determine distances between the vehicle and a nearby object, as well as the rate of change of distance to an object. Furthermore, manufacturers are increasingly designing these systems to operate in multiple directions, where automobiles can transmit ultrasonic signals in multiple directions to detect objects, including other vehicles, using echo detection. As a result, there can be multiple ultrasonic transmitters operating nearby each other, causing cross talk and other interference which makes it difficult to determine the distance to objects which produce echoes. Accordingly, interference issues need to be addressed in order for such distance measurements to be reliable.